This invention generally relates to methods and apparatus for enhancing the air quality in buildings, and more specifically, to methods and apparatus for enhancing the air quality in buildings during a chemical and/or biological attack and/or when the air quality around a building drops to unacceptable levels.
The recent demise of the cold war and decline in super-power tensions has been accompanied by an increase in concern over the viability of weapons of mass destruction such as chemical and biological (CB) weapons. CB weapons include chemical agents such as phosgene, nerve agents such as Sarin, and biological agents such as anthrax, botulism, plaque, tularemia, and small pox. CB weapons may be delivered to occupants of a building in any number of ways, including the release of agents in or around the building. In some cases, the building""s heating, ventilating, and air conditioning (HVAC) system may be used to help deliver the released agent into the building. Agents may also be released within public spaces of a building, and dispersed to other, private areas of the building via the buildings HVAC system.
In addition, and especially in urban settings, smog or other environmental contaminates can be present in and around buildings. Smog may be generated from cars, industrial plants, and other sources. To this end, the United States Environmental Protection Agency (EPA) often issues smog alerts when high concentrations of ground-level ozone (the main component of smog) are predicted in a given geographical area. Chemical spills or leaks may also be a source of released contaminates. Despite filtration, a building""s HVAC system can deliver some of the smog and/or other contaminates into the building.
What would be desirable, therefore, are methods and apparatus for enhancing the air quality in buildings, and more specifically, methods and apparatus for enhancing the air quality in buildings during a chemical and/or biological attack and/or when the air quality around a building drops to unacceptable levels.
The present invention provides methods and apparatus for enhancing the air quality in buildings during a chemical and/or biological attack and/or when the air quality around a building drops to unacceptable levels. In a preferred embodiment, relatively non-contaminated (i.e. clean) air is stored in one or more clean air reservoirs. Once stored, the clean air is selectively delivered to buildings when a chemical and/or biological attack is detected, and/or when the air quality around a building drops to unacceptable levels.
In one illustrative embodiment, a reservoir is provided for storing air. A conduit is provided for transferring the stored air to the interior space of one or more buildings. A valve may be provided for selectively allowing the air stored in the reservoir to be transferred through the conduit to the one or more buildings. In some embodiments, a compressor may be used to pressurize the air that is stored in the reservoir, and/or a tensioning system may be used to help reduce the volume of the air reservoir as air is released from the reservoir. The valve may be controlled so that the pressure of the released air is substantially constant over time.
In some embodiments, the compressor is shut down when the air at the inlet of the compressor is subject to a chemical and/or biological agent or when the air quality drops below unacceptable levels. This may help prevent the air in the reservoir from becoming contaminated. Filters may also be provided.
In some embodiments, the air reservoir is an underground reservoir. The underground reservoir may be man-made or naturally occurring. For example, the underground reservoir may be a cavern in the ground, a salt dome, an ice cavern, a tunnel, a storm sewer, or any other underground cavity or opening. Alternatively, the reservoir may be an above ground reservoir. For example, the reservoir may be a converted grain elevator, water tower, petroleum storage tank, inflatable building, or any other suitable structure.
In some embodiments, the reservoir may include a sealing layer. The sealing layer may include, for example, a cement layer, an elastomeric layer, or any other suitable layer capable of providing an air seal and/or support to the air reservoir. Alternatively, or in addition, an air bladder may be inserted into the reservoir. The inner walls of the reservoir may provide support to the air bladder when the air inside the air bladder is pressurized.
Methods for converting an existing structure into a clean air reservoir are also contemplated. For example, in one illustrative method, an existing structure is sealed to provide a reservoir for storing air. A conduit is provided for transferring the stored air to one or more buildings. Finally, a valve is provided for selectively allowing the stored air to be transferred from the air reservoir, through the conduit, and into the one or more buildings.
Methods for accepting the clean air supply into a building are also contemplated. For example, in one illustrative method, both the air intake and air exhaust of the building are closed. The clean air supply is then accepted, and a positive air pressure is maintained in the building. When the building has two or more floors, air may also be pumped from a lower floor to one or more upper floors and/or from an upper floor to one or more lower floors to help reduce pressure differentials between floors. Maintaining a positive pressure in buildings may help keep external contaminates from entering the building.
In another illustrative method, the clean air is directed into the ventilation system of a building to help improve the air quality in the building. The air intake of the building may be left open, partially closed, or closed altogether. The clean air supply may be used to replace or supplement the air that is normally drawn from the air intake of the building. The remainder of the building""s HVAC system may operate in a conventional manner, if desired. This method may be particularly useful when, for example, smog or the like is detected in or around a building.